Heavy Shreddin is a video game about snowboarding that was released for the Nintendo Entertainment System in 1990.
There are three mountains that the player must overcome in order to complete the game. As the player descends the mountain the terrain becomes more and more difficult to navigate. There are three degrees of difficulty on each of the mountains. The first is novice (marked by a circle), the second is intermediate (marked by a square), and the third is expert (marked by a diamond).
Source: Wikipedia, "Heavy Shreddin'", available under the CC-BY-SA License.